Felines are susceptible to infection by retroviruses (e.g., feline immunodeficiency virus (FIV) and feline leukemia virus (FELV)). FIV is the causative agent of feline immunodeficiency disease syndrome. FELV is caused by a feline retrovirus that is similar to human leukemia virus in humans. Feline leukemia virus induces the uncontrolled growth of blood cells.
Feline retroviruses affect a significant portion of the feline population. For example, approximately 2.5% to 4.4% of cats worldwide were estimated to be infected with FIV in 2005 (Richards, Biologicals 33:219, 2005). Approximately 0.5% of domestic felines are persistently infected with FELV. Successful treatment of FIV and FELV infection in felines (e.g., domestic and feral felines) is desired.